Motorcycle Repair: Sportster mufflers, dyna jet, sportster 1200

Question
Hy! I have a 2004 Sportster 1200 Roadster and I've just bought a pair of stock mufflers on ebay for a few bucks... I'd like to modify them to give my sporty a new and more powerfull voice. How can I do that? If I open them in the back Are there any problems I could have (carburetion or somethig else)? My english is not perfect but I hope you understand what I mean! THANK U MUCH;André

Answer
Your bike came from the factory lean to pass the EPA. You can drill a few holes in the baffles to make it louder, but that will make it run ever leaner. To richen it back up you can install a Dyna-Jet kit. This will richen it back up and give you more throttle responce.
Good luck and happy riding
Mike